Electronic control device

ABSTRACT

Provided is a highly reliable electronic control device which has not only an effect of reducing costs but also an effect of facilitating a manufacturing process. To include a control board; a connector including a terminal connected to the control board; and a housing case to which the control board and the connector are fixed. The control board has a part sealed with a sealing resin. The connector is disposed at a position facing another part of the control board, being isolated from the sealing resin by the control board and the housing case.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This U.S. non-provisional patent application is a continuation of U.S.patent application Ser. No. 16/060,716 filed on Jun. 8, 2018, whichclaims priority under 35 U. S U.S.C. § 119 of Japanese PatentApplication No. 2015-240709, filed on Dec. 10, 2015, and InternationalApplication No. PCT/JP2016/081654, filed on Oct. 26, 2016, the wholecontents of which are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to an electronic control device such as anengine control unit and an automatic transmission control unit which aremounted on automobiles, and particularly relates to a structure of anelectronic control device.

BACKGROUND ART

With a background of environmental issues and energy issues, more andmore automobiles are mounted with electrical components at anaccelerating rate, leading to a great increase in the number ofelectronic control devices mounted on an automobile. Such an increase inthe number limits places to mount electronic control devices, and it isinevitable to mount the electronic control devices in an engine roomwhich is under severe environment in an automobile. On the other hand,expansion of a cabin space for the purpose of improving amenity of anautomobile leads to downsizing of an engine room. In such manners, alarge number of electronic control devices and wire harnesses thereofare arranged in a downsized engine room, so that problems such asdifficult layout, weight increase, and cost increase are to be solved.Therefore, there is a demand for downsizing, weight reduction, and costreduction of electronic control devices. In addition to thoserequirements, there is a tendency of shortening wire harnesses. Alongwith this tendency, an engine control device, for example, is mountedmuch closer to an engine than ever before, and there is concern thathigh heat and high vibration of the engine may affect the engine controldevice.

Therefore, improvements in resistance to high temperatures andresistance to vibrations are required in electronic control devices. Asa countermeasure for the requirement, there is known a structure inwhich a control board mounted with electronic components is sealed withresin. Sealing the control board with resin enables reduction in thermalinfluences on the electronic components and enables suppression ofvibrations of the board under vibrational environment. However, thestructure of resin seal has harmful effects due to resin molding, sothat countermeasures for the effects are required (PTL 1).

The electric electronic module described in PTL 1 includes an electroniccircuit board on which an electronic circuit is mounted; a metal base onwhich the electronic circuit board is mounted; and a connector, in whichthe electronic circuit board is sealed with resin. In such aconfiguration, a potting resin or a premold resin is filled inside theconnector. Such a sealing resin prevents deformation of a connectorhousing caused by resin molding pressure. In addition, as an exemplarymethod not using a potting resin, an alignment plate is fixed to themetal base so as to prevent the sealing resin from flowing into theconnector.

CITATION LIST Patent Literature

-   PTL 1: JP 2007-273796 A

SUMMARY OF INVENTION Technical Problem

However, the technique disclosed in PTL 1 requires the use of a pottingresin to fill inside the connector, which increases costs and the numberof steps in a production process. Furthermore, in a case where analignment plate is used, the alignment plate is deformed by resinmolding pressure so that a connector terminal may be deformed, which mayaffect the reliability.

An object of the present invention is to provide a highly reliableelectronic control device which has not only an effect of reducing costsbut also an effect of facilitating a manufacturing process.

Solution to Problem

The present invention includes: a control board; a connector including aterminal connected to the control board; and a housing case to which thecontrol board and the connector are fixed, wherein the control board hasapart sealed with a sealing resin, the connector is disposed at aposition facing another part of the control board, and the connector isisolated from the sealing resin by the control board and the housingcase.

Advantageous Effects of Invention

According to the present invention, it is possible to manufacture ahighly reliable electronic control device at a low cost and with asimple manufacturing process.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view and a cross-sectional view of an electroniccontrol device according to a first embodiment of the present invention.

FIG. 2 is a view showing an assembly procedure of the electronic controldevice according to the first embodiment of the present invention.

FIG. 3 is a plan view and a cross-sectional view of an electroniccontrol device according to a second embodiment of the presentinvention.

FIG. 4 is a plan view and a cross-sectional view of an electroniccontrol device according to a third embodiment of the present invention.

FIG. 5 is a plan view and a cross-sectional view of an electroniccontrol device according to a fourth embodiment of the presentinvention.

DESCRIPTION OF EMBODIMENT

An embodiment of the present invention will now be described withreference to the accompanying drawings. In the drawings, the samemembers are denoted by the same reference numerals, and duplicateexplanation will be omitted as appropriate.

First Embodiment

FIG. 1(a) is a plan view of an electronic control device according to afirst embodiment of the present invention, FIG. 1(b) is across-sectional view in the direction of the arrow A-A of FIG. 1(a), andFIG. 1(c) is a cross-sectional view in the direction of the arrow B-B ofFIG. 1(a). FIG. 2 is a view showing an assembly procedure of theelectronic control device according to the first embodiment of thepresent invention.

As shown in FIG. 1, an electronic control device 1 includes a controlboard 3 on which an electronic component 2 such as a microcomputer ismounted; a housing case 4; and a connector 5. The control board 3 ismolded with a sealing resin 6.

As shown in FIG. 1(b), the housing case 4 includes a vehicle fixing unit4 a configured to fix the electronic control device 1 to a vehicle; aconnector-mounting unit 4 b; a control board-mounting unit 4 c; and aframe 4 d that surrounds the connector 5. These members are molded withthe housing case 4 in an integrated manner. A preferable example of amaterial of the housing case 4 includes a metallic material having highthermal conductivity, shielding property, and rigidity. From viewpointsof mass productivity, weight reduction, radiation performance, andcosts, the housing case 4 preferably includes aluminum or an aluminumalloy. The housing case 4 may be subjected to surface treatment such assurface roughening, and alumite treatment. Accordingly, an adhesionforce between the housing case 4 and the sealing resin 6 is enhanced,and the sealing resin 6 is hardly peeled off with respect to stresscaused by changes in ambient temperature or by vibrations, whichimproves the reliability of the electronic control device 1.

As shown in FIG. 1(b), the connector 5 includes a connector terminal 5 aconfigured to connect a vehicle harness with the control board 3; and aconnector housing 5 b configured to align and hold the connectorterminal 5 a at a specified pitch. From viewpoints of conductivity,downsizing, and costs, a material of the connector terminal 5 a may becopper, or a copper alloy. From viewpoints of lightweight and excellencyin heat resistance, preferable materials of the connector housing 5 bare polybutylene terephthalate (PBT) resin, polyamide (PA) 66 resin, andpolyphenylene sulfide (PPS) resin.

Hereinafter, the assembly procedure of the electronic control device 1will be described with reference to FIG. 2.

First, as shown in FIG. 2(c), the connector 5 is inserted into thehousing case 4 and attached to the same. At that time, an adhesive sealmaterial 7 is applied in advance to the connector-mounting unit 4 b ofthe housing case, the connector 5 is then placed on theconnector-mounting unit 4 b, and the seal material 7 is cured.Accordingly, it is possible to prevent foreign matters, water, and thelike from entering into the electronic control device 1 from a gapbetween the housing case 4 and the connector 5. Furthermore, using theadhesive seal material 7 makes it possible to fix the connector 5 to thehousing case 4. If required, a screw may be used for fixing.

Next, as shown in FIG. 2(d), the electronic component 2 such as amicrocomputer is mounted on the control board 3. As for the controlboard 3, a resin wiring board based on glass epoxy resin or the like isused. When mounting the electronic component 2 on the control board 3,lead-free solder is used such as Sn—Cu solder, Sn—Ag—Cu solder, andSn—Ag—Cu—Bi solder.

Next, as shown in FIG. 2(e), the control board 3 is attached to thehousing case 4, and a sub-assembly 10 is assembled. At that time, thecontrol board 3 is placed on the control board-mounting unit 4 c of thehousing case 4, and the control board 3 is fixed to the housing case 4with a screw 8. The number of points fixed by the screw 8 is preferably3 or more. At that time, the adhesive seal material 7 is applied to alower end face (contact portion) of the frame 4 d that comes intocontact with the control board 3, the control board 3 is then placed onthe frame 4 d, and the seal material 7 is cured. Accordingly, it ispossible to reliably prevent the sealing resin 6 from entering aresin-unsealed space 9 defined by the control board 3, the housing case4, and the connector 5. Isolation of the connector 5 from the sealingresin 6 prevents deformation of the connector 5 due to resin moldingpressure. Furthermore, adhesively fixing the control board 3 to thehousing case 4 makes it possible to prevent deformation of the controlboard 3 due to resin molding pressure. Still further, providing theframe 4 d in the existing housing case 4 makes it possible to form theresin-unsealed space 9 without any additional components such as acover.

With regard to connection between the connector 5 and the control board3, the connector terminal 5 a is inserted into a through hole 3 a of thecontrol board 3, and those members are joint by lead-free solder such asSn—Cu solder, Sn—Ag—Cu solder, and Sn—Ag—Cu—Bi solder. It should benoted that the connector 5 may be of a surface-mount type or a press-fittype.

Next, as shown in FIG. 2(f), the sub-assembly 10 is set in a die 11 forresin seal. In this embodiment, the sub-assembly 10 is set in a movableupper die 11 a, and as the upper die 11 a moves, the sub-assembly 10 isset in a fixed lower die 11 b. An upper surface of the housing case 4and a surface of the vehicle fixing unit 4 a which are not to be moldedwith the sealing resin 6 are directly pressed by the die 11 so as not tocome into contact with the resin at the time of resin molding.

In order to secure fluidity of the sealing resin 6 and to meticulouslyfill the sealing resin 6 into the metal die 11, the metal die 11, thesub-assembly 10, and the sealing resin 6 may be preheated. The sealingresin 6 may be a thermosetting epoxy resin, an unsaturated polyesterresin, or a thermoplastic resin. Examples of a sealing method includetransfer molding, compression molding, injection molding, and hot meltmolding. With regard to physical properties of the sealing resin 6, itis preferable that linear expansion coefficient is in a range of 10 to30×10-6/° C., and thermal conductivity is in a range of 0.5 to 3 W/mK.

After filling the sealing resin 6 into the die 11 and curing the resin,the resin molded article is taken out of the die 11, and the electroniccontrol device 1 with the resin-unsealed space 9 as shown in FIG. 2(g)is completely manufactured.

If there are electronic components 2 a and 2 b which are not sealed withresin, the electronic components 2 a and 2 b may be mounted in advanceon a part of the control board 3 which is exposed to the resin-unsealedspace 9 as shown in FIG. 1(c). With regard to the electronic component 2b which is taller than the housing case 4, it is disposed directly underthe connector 5, and the connector housing 5 b is shaped to correspondto the electronic component 2 b. Accordingly, while the height of theelectronic control device 1 is controlled, the control board 3 can bemounted with the electronic component 2 b that has a larger height thanthat of the electronic components 2 and 2 a mounted on other parts. Anexample of the electronic components 2 a and 2 b disposed in theresin-unsealed space 9 includes an electrolytic capacitor. In anelectrolytic capacitor, a small amount of an electrolytic solutioninside the capacitor is usually vaporized and leaked to the outside.Therefore, sealing the electrolytic capacitor with resin causesaccumulation of vaporized gas around an electrode of the electrolyticcapacitor, which may lead to short-circuiting. Furthermore, anelectrolytic capacitor is generally provided with an explosion-proofvalve that releases gas in a case where internal gas pressure becomeshigh. However, sealing the electrolytic capacitor with resin disablesthe function of an explosion-proof valve so that gas cannot be released.As alternative components of the electrolytic capacitor, aresin-sealable tantalum capacitor, a ceramic capacitor, and the like maybe used, but these capacitors are expensive than the electrolyticcapacitor and leads to cost increase of the electronic control device 1.

According to the electronic control device 1 of this embodiment, as theconnector 5 is isolated from the sealing resin 6 by the frame 4 d moldedwith the housing case 4 in an integrated manner, it is possible toprevent the deformation of the connector 5 caused by the resin moldingpressure and to prevent the deformation of the terminal, which ensuresthe reliability of the electronic control device 1.

In addition, only providing the frame 4 d in the existing housing case 4makes it possible to form the resin-unsealed space 9 and to dispose arelatively inexpensive electrolytic capacitor in the resin-unsealedspace 9, which allows cost reduction of the electronic control device 1.

Second Embodiment

An electronic control device according to a second embodiment of thepresent invention will now be described, focusing on differences fromthe first embodiment. FIG. 3(a) is a plan view of the electronic controldevice according to this embodiment, FIG. 3(b) is a cross-sectional viewin the direction of the arrow A-A of FIG. 3(a), and FIG. 3(c) is across-sectional view in the direction of the arrow B-B of FIG. 3(a).

In FIG. 3, a housing case 4 of an electronic control device 1 includes aframe 4 e molded in an integrated manner. The frame 4 e is disposedoutside a frame 4 d that surrounds a connector 5, protruding from asurface opposing a control board 3 of the housing case 4, andsurrounding an electronic component 2 c which is disposed on the controlboard 3 and is not sealed with resin. When the control board 3 isattached to the housing case 4, a seal material 7 is applied to a lowerend face (contact portion) of the frame 4 e that comes into contact withthe control board 3, the control board 3 is then placed on the frame 4e, and the seal material 7 is cured. Accordingly, a resin-unsealed space12 is formed around the resin-unsealed electronic component 2 c, andwhen the entire control board 3 is molded with the sealing resin 6, itis possible to prevent ingress of the sealing resin 6 around theelectronic component 2 c. Therefore, the electronic control device 1according to this embodiment is preferable in a case where theresin-unsealed electronic component 2 c cannot be disposed directlyunder the connector 5 due to restrictions on layout of components on thecontrol board 3.

According to the electronic control device 1 of this embodiment, thefollowing effects can be obtained in addition to effects similar tothose of the first embodiment.

As the frame 4 e is provided outside the frame 4 d that surrounds theconnector 5, it is possible to form the resin-unsealed space 12 notbeing affected by the ingress of the sealing resin 6 at a place otherthan the place directly under the connector 5, so that it is possible tofacilitate layout of the resin-unsealed electronic component 2 c.

Third Embodiment

An electronic control device according to a third embodiment of thepresent invention will now be described, focusing on differences fromthe second embodiment. FIG. 4(a) is a plan view of the electroniccontrol device according to this embodiment, FIG. 4(b) is across-sectional view in the direction of the arrow A-A of FIG. 4(a), andFIG. 4(c) is a cross-sectional view in the direction of the arrow B-B ofFIG. 4(a).

As in FIG. 4, an electronic control device 1 according to thisembodiment includes a housing case 4 provided with a through hole 4 fthat links outside air with a resin-unsealed space 12 where anelectronic component 2 c is disposed, and the electronic control device1 includes a breathing filter assembly 13 which is attached to thethrough hole 4 f and has air permeability but not water permeability.Therefore, the electronic control device 1 according to this embodimentis preferable in a case where the resin-unsealed electronic component 2c cannot be disposed directly under a connector 5 due to restrictions onlayout of components on a control board 3 and in a case where it isrequired to maintain ambient air pressure of the electronic component 2c to be equivalent to air pressure of the outside air.

According to the electronic control device 1 of this embodiment, thefollowing effects can be obtained in addition to effects similar tothose of the second embodiment.

It is possible to maintain the air pressure of the resin-unsealed space12 provided with the electronic component 2 c to be equivalent to theair pressure of the outside air, so that the control board 3 can bemounted with, for example, a sensor or the like that measures pressureof the outside air.

In a case where an electronic component 2 b whose ambient air pressureis required to be maintained at a level equivalent to the air pressureof the outside air is disposed directly under the connector 5, it shouldbe noted that a through hole 5 c that links the outside air with theinside of a frame 4 e (resin-unsealed space 9) may be provided in aconnector housing 5 b, as shown in FIG. 4(c), and a breathing filtermembrane 14 having air permeability but not water permeability may beattached to the through hole 5 c with an adhesive or by thermal welding.

Fourth Embodiment

An electronic control device according to a fourth embodiment of thepresent invention will now be described, focusing on differences fromthe first embodiment. FIG. 5(a) is a plan view of the electronic controldevice according to this embodiment, FIG. 5(b) is a cross-sectional viewin the direction of the arrow A-A of FIG. 5(a), and FIG. 5(c) is across-sectional view in the direction of the arrow B-B of FIG. 5(a).

In FIG. 5, an electronic control device 1 according to this embodimenthas such a configuration that a frame 4 d is not molded with a housingcase 4 in an integrated manner and includes another member (hereinafterreferred to as “sealing resin-ingress prevention member”) 15. When thesealing resin-ingress prevention member 15 is attached to the housingcase 4, a seal material 7 is applied to an upper end face the sealingresin-ingress prevention member 15, the seal material 7 is then bondedto a lower surface of the housing case 4 and cured. When a control board3 is attached to the housing case 4, the seal material 7 is applied to alower end face (contact portion) of the sealing resin-ingress preventionmember 15 that comes into contact with the control board 3, the controlboard 3 is then placed on the sealing resin-ingress prevention member15, and the seal material 7 is cured.

According to the electronic control device 1 of this embodiment, thefollowing effects can be obtained in addition to effects similar tothose of the third embodiment.

The frame 4 d is not molded with the housing case 4 in an integratedmanner and includes the sealing resin-ingress prevention member 15, sothat the degree of freedom of a material and shape of the frame 4 d isimproved, and it is possible to design the frame 4 d corresponding todemand characteristics. Therefore, the electronic control device 1 showsthe desired effect of improvement in reliability.

In addition, since the frame 4 d can be manufactured independently fromthe housing case 4, even in a product model that includes an electroniccomponent 2 laid outed differently, the housing case 4 can be sharedwithout manufacturing a dedicated housing case 4. Therefore, only bychanging the layout of the sealing resin-ingress prevention member 15makes it possible to cope with model change. Accordingly, the electroniccontrol device 1 shows the desired effect of cost reduction.

Although the embodiments of the present invention have been described indetail, the present invention is not restricted to the aforementionedembodiments and includes various modifications. For example, theaforementioned embodiments have been described in detail to give cleardescriptions to the present invention. It should be noted that thepresent invention is not restricted to the one including the wholeconfigurations described above. In addition, a configuration of anembodiment may be partially added to a configuration of anotherembodiment. Alternatively, a part of a configuration of an embodimentmay be deleted or replaced by a part of another embodiment.

REFERENCE SIGNS LIST

-   1 electronic control device-   2, 2 a, 2 b, 2 c electronic components-   3 control board-   3 a through hole-   4 housing case-   4 a vehicle fixing unit-   4 b connector-mounting unit-   4 c control board-mounting unit-   4 d frame (first frame)-   4 e frame (second frame)-   4 f through hole (first through hole)-   5 connector-   5 a connector terminal-   5 b connector housing-   5 c through hole (second through hole)-   6 sealing resin-   7 seal material-   8 screw-   9 resin-unsealed space (first resin-unsealed space)-   10 sub-assembly-   11 die-   11 a upper die-   11 b lower die-   12 resin-unsealed space (second resin-unsealed space)-   13 breathing filter assembly-   14 breathing filter membrane-   15 sealing resin-ingress prevention member

1. An electronic control device comprising: a control board that has apart sealed with a sealing resin; a connector that is disposed at aposition facing another part of the control board and includes aterminal connected to the control board; and a housing case to which thecontrol board and the connector are fixed, wherein the housing casecomprises a first frame which surrounds the connector and comes intocontact with the control board, and wherein the connector is isolatedfrom the sealing resin by the control board and the housing caseincluding the first frame.
 2. An electronic control device comprising: acontrol board that includes a part of the control board is sealed with asealing resin; a connector including a terminal connected to the controlboard; and a housing case to which the control board and the connectorare fixed, wherein the housing case comprises a first frame whichsurrounds the connector and comes into contact with the control board,and another part of the control board forms a resin-unsealed spacetogether with the first frame of the housing case and the connector, theresin-unsealed space not being sealed with resin.
 3. The electroniccontrol device according to claim 2, wherein the control board includesa part mounted on the resin-unsealed space.
 4. An electronic controldevice in which a control board is fixed inside a housing case and thecontrol board is connected to a connector through a terminal, theelectronic control device being configured to exchange a signal with theoutside, wherein the electronic control device comprises: a first framewhich surrounds the connector and comes into contact with the controlboard, a connector holding unit provided with a gap between theconnector and the control board by the first frame so as to hold theconnector in the housing case; and a first resin-unsealed space whichcooperates with the control board, the first frame and the connector toprevent ingress of sealing resin into the gap.
 5. The electronic controldevice according to claim 4, wherein the first frame includes a memberdifferent from the housing case.
 6. The electronic control deviceaccording to claim 4, wherein the housing case comprises a second framewhich comes into contact with the control board outside the first frame,and the electronic control device is formed with a second resin-unsealedspace which is not affected by the ingress of the sealing resin betweenthe housing case, the second frame, and the control board.
 7. Theelectronic control device according to claim 6, wherein the controlboard includes a part mounted on the first resin-unsealed space and thesecond resin-unsealed space.
 8. The electronic control device accordingto claim 6, wherein the electronic control device is provided with anadhesive seal material at contact portions between the first frame andthe control board, and the second frame and the control board.
 9. Theelectronic control device according to claim 6, wherein the housing caseis provided with a first through hole that links the secondresin-unsealed space with outside air, and the first through hole isprovided with a breathing filter assembly which has air permeability butnot water permeability.
 10. The electronic control device according toclaim 7, wherein the connector includes a connector housing providedwith a second through hole that links the first resin-unsealed spacewith outside air, and the second through hole is provided with abreathing filter membrane which has air permeability but not waterpermeability.
 11. The electronic control device according to claim 7,wherein the control board includes a part which is mounted on the firstresin-unsealed space and higher than the other part of the control boardmounted on the second resin-unsealed space.
 12. The electronic controldevice according to claim 10, wherein the connector housing of theconnector has a shape corresponding to a shape of an electroniccomponent disposed in the first resin-unsealed space.
 13. The electroniccontrol device according to claim 1, wherein the sealing resin is athermosetting resin.
 14. The electronic control device according toclaim 2, wherein the sealing resin is a thermosetting resin.
 15. Theelectronic control device according to claim 3, wherein the sealingresin is a thermosetting resin.